Tuning of cavities in a klystron is accomplished by adjusting inductive shorting bars that are internal to the cavity assemblies within the vacuum envelope. The shorting bars are moved by pushing or pulling plungers which enter the cavities through hermetic bellows.
A tuner is a device for operating the plungers of a klystron so that the klystron can be precisely and repeatedly tuned to certain preselected channel frequencies within a band of frequencies. Examples of prior art tuners are shown in U.S. patents Nos., 3,132,280 and 3,617,799, both assigned to the assignee of the subject invention.